/*
 * @(#) $Header$
 *
 * Copyright (C)  2006  Daniel Léonard
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package ca.forklabs.baselib.util;

/**
 * An {@code UnaryFunction} is a function object that takes an object,
 * does some operation on it and then returns a result, which can be
 * {@code null}.
 *
 * @param   <R>   the type of the returned object.
 * @param   <A>   the type of the argument object.
 *
 * @author   <a href="mailto:forklabs at gmail.com?subject=ca.forklabs.baselib.util.UnaryFunction">Daniel Léonard</a>
 * @version $Revision$
 */
public interface UnaryFunction<R, A> {

   /**
    * Performs an operation on the specified object.
    * @param   arg   an object.
    * @return   the result of the operation.
    */
   public R invoke(A arg);

   }
